Manual transmissions are being reconsidered because they provide a more efficient powertrain due to the reduction in the amount of fluid power that is required to control the automatic shifting planetary transmission. Planetary manual transmissions are being considered because of the lower cost and mass of planetary gears relative to countershaft gears. When using planetary transmissions, it is necessary to engage two or more torque-transmitting mechanisms substantially simultaneously in order to produce a usable drive ratio within a planetary gear arrangement. In these more conventional automatic transmissions, the torque-transmitting mechanisms are fluid-operated devices controlled by a plurality of valves and electronic controls. This permits the selective actuation and deactuation of the torque-transmitting mechanisms.
Manual planetary transmissions, however, employ synchronizer type torque-transmitting mechanisms, which are mechanical in nature and are generally controlled by a shift rod, which is under the manipulative control of the operator. In manual planetary transmissions, it is necessary to engage and/or disengage two synchronizers to establish a drive ratio through a planetary gear arrangement. One such mechanical shift control mechanism is shown in U.S. Pat. No. 6,835,157, issued Dec. 28, 2004, in the name of Haka and assigned to the assignee of this application.